package com.sanbuTech.util;

public class RandomUtil {

	/**
	 * 创建指定数量的随机字符串
	 * 
	 * @param numberFlag 是否是数字
	 * @param length 长度
	 * @return
	 */
	public static String createRandom(boolean onlyNumber, int length) {
		String retStr = "";
		String strTable = onlyNumber ? "1234567890" : "1234567890abcdefghijkmnpqrstuvwxyz";
		int len = strTable.length();
		boolean bDone = true;
		do {
			retStr = "";
			int count = 0;
			for (int i = 0; i < length; i++) {
				double dblR = Math.random() * len;
				int intR = (int) Math.floor(dblR);
				char c = strTable.charAt(intR);
				count++;
				retStr += strTable.charAt(intR);
			}
			if (count >= length) {
				bDone = false;
			}
		} while (bDone);

		return retStr;
	}
	
	public static void main(String[] args) {
		System.err.println(RandomUtil.createRandom(false, 18));
	}
}
